Dehydrochlorination of chlorinated fatty acids and esters



Patented Apr. 5, 1949 2,488,340 DEHYDROCHLORINATION OF CHLORIN- I ATED FATTY ACIDS AND ESTERS George R. Van Atta, Berkeley, and William. C.- Dietrich, El Cerrito, CaliL, assignors to United States of America as represented by the Secretary of Agriculture No Drawing. Application April 2, 1947, Serial No. 738,907

17 Claims. (Cl. 260-405.5)

(Granted under the act of March 3, 1883, as amended April 30, 1928; 370 O. G. 757) This application is made under the act of March 3, 1883, as amended by the act of April 30, 1928, and the invention herein described, if

patented, may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment to us of any royalty thereon.

This invention relates to the preparation of unsaturated, high-molecular weight, long chain fatty acids and the alkyl esters thereof by the dehydrochlorinationfof chlorinated, high-molecular weight, long chain'fatty acids, particularly those having from 8 to 20 carbon atoms, and the alkyl esters thereof.

The invention has among its objects the provision of a process for the preparation of unsaturated, high molecular weight, long chain fatty acids and the alkyl esters thereof for use in the manufacture of soaps, and of other detergents in which good solubility, wetting power, and freelathering properties are desired, and also for use in the manufacturing of drying oils and plasticizers. Other objects will be apparent from the description of the invention.

As used herein, the term dehydrochlorination means the chemical reaction involving the removal of hydrogen chloride from the molecule of the chlorinated compound. This reaction can be illustrated by the following equations:

Dehydrochlorination of monochlorostearic acid C1'IH34C1COOH C17H33COOH+HC1 2. Dehydrochlorination of dichlorostearic acid Distinction between variations of these two methods has rested in the past upon choice of chlorinating agent, or alkali, diluents, and materials to absorb or react with the hydrogen chloride evolved. Although various temperatures and pressures have been employed, there has been apparently no attempt to vaporize completely the chlorinated long-chain fatty materials and to accomplish unsaturation whfle the materials are in the vapor phase.

We have found that it is not practicable to de hydrochlorinate chlorinated fatty acids or their esters by heating the liquid materials at atmospheric pressure. For example, in periods of heating at 200 C. for 8 to 15 hours in an-inert atmosphere and under strong agitation, only about half the chlorine was removed from chlorinated palmitic acid which originally contained between 21.5 and 22 percent of chlorine. Moreover, such long periods of heating appeared to encourage undesired side reactions, and at least the bulk of the remaining chlorine appeared to be held no more firmly than that removed earlier in the process, since further quantities could be removed by continued heating under the same conditions. Further evidence of this progressive decomposition is observed when attempts are made to free the products of their very dark color. by vacuum distillation. Substantially all the combined chlorine must be removed from such materials if clear, pale, and stable products are to be obtained by vacuum distillation.

Dehydrochlorination is promoted by raising the I heating. The effect of these latter reactions be-' comes excessive if attempts are made to eflect substantially complete dehydrochlorination by increasing treatment temperature alone.

Reduction of pressure favors dehydrochlorinationin accordance with the law of mass action, but so long as the chlorinated fatty material remains liquid the process is slow and the other disadvantages mentioned persist.

It has now been found, however, that if the dehydrochlorination is conducted in the presence of a dehydrochlorination,catalyst and under condi-- tions of temperature and reduced pressure such that the reaction takes place in the vapor phase, separation of hydrogen chloride from the molecules of chlorinated fatty material is greatly accelerated and at the same time other types of decomposition favored by either prolonged heating or very high temperature are minimized. It was found that the catalyst has the specific eifect of increasing the rate of hydrogen chloride removed, and hence, products of a high degree of unsaturation are obtained within a very short period of treatment.

It is preferred that dehydrochlorination be conducted at a temperature of about from 220 to 300 C. and at a pressure of less than about 5 mm. of mercury, and more preferably at a pres- H by heating them in the presence of a dehydro- 1o chlorination catalyst and in the absence ofair to a temperature above that at which they boil under the reduced pressure employed. It is necessary to maintain the reacting materials in the vapor phase for only a very brief period in order to effect substantially complete dehydrochlorination of the chlorinated fatty materials. After this short period (about 0.01 to 5 seconds) of heating, the vapors, still under reduced pressure, are cooled promptly to such a temperature that substantially all their organic components are condensed to liquid. The hydrogen chloride, which after cooling remains in the gaseous phase, is withdrawn by suction to be separately recovered or disposed of as desired.

The process herein described and claimed is an extension and improvement of the process set forth in the application of George R. Van Atta and David F. Houston, Serial No. 549,082, flied August 11, 1944, now Patent No. 2,430,897. 80

By processing in the manneroutlined above, the following ends are achieved: l. Vapor-phase dehydrochlorinatlon is accomplished in a very brief period of heating, in contrast to the prolonged treatment necessary in 85 liquid-phase operation.

2. Besides effecting an economy in time, the short period of heating lessens opportunity for formation of undesired products of side reactions. 1 40 3. Dehydrochlorination is carried far beyond the limits practicable in liquid-phase operations performed on the free acids or esters.

4. Clear, pale-colored unsaturated products,

which are stable with respect to color and chiccost is avoidedand the products are obtained without contamination.

7. Vapor-phase dehydrochlorination, in contrast to other methods, is especially suited to conflnuous-type operations with their characteristic opportunities for cost economies. so

8. Dehydrochlorination is eflected without hydroxylation. In processes involving use of water and alkali, hydroxy compounds are formed invariable quantity.

9. Use of the catalyst causes more rapid dehydrochlorination and gives a product containing a higher degree of unsaturation. Further, use of the catalyst permits employment of lower temperatures whereby side reactions are minimized.

In accordance with this invention, high molecular weight chlorinated fatty acids or their esters, particularly those having from 8 to 20 carbon atoms, are fed, in the vapor state, at controlled rates into a heated dehydrochlorination dehydrochlorination, being 50 ber. Disruption of the chlorinated material begins immediately and continues during the very brief intervalrequired for the vapors to traverse the chamber to the outlet under the influence of suction. Upon emerging from the reaction chamber the vapors enter a heat exchanger, where the now unsaturated fatty material is condensed to a liquid by cooling. 7

From the heat exchanger, the liquefied product flows into receiving vessels. During continuous operations, the stream of product is directed by means ofvalves alternately into one and another of the collectors. This permits withdrawal of the product from the collectors as they becomefllled without interrupting the dehydrochlorinationprocess.

' The hydrogen chloride remains in the vapor phase and passes from the heat exchanger through an outlet under the influence of suction.

Design of the dehydrochlorination equipment, selection of mechanical accessories, and position of the various parts of the apparatus are matters in which wide freedom of choice may be exercised. In one of the forms of the apparatus that has proved convenient, a U-shaped tube was immersed in a heated oil bath. The chlorinated material is introduced into one leg of the tube which acts as an evaporator. The other leg of the tube is packed with the dehydrochlorination catalyst, and this latter leg acts as the reaction chamber. The last-mentioned leg of the tube is attached to a source of vacuum through a condenser.

Another form of apparatus was better adapted to larger scale operation. In this device the reaction chamber consisted of a vertical glass tube packed with the dehydrochlorination catalyst and surrounded by an electrical heating device. The reaction tube was connected at its lower end to a preheating tube which served to vaporize chlorinated material entering the system. The vapors of chlorinated material pass up through the reaction tube and are then led into a condenser where the product is cooled to a liquid and removed from the system while the vapors of hydrogen chloride pass through the condenser to a scrubber which removes any small traces of organic product that may have escaped condensation.

Considerable latitude in choosing the materials to be used for constructing the dehydrochlorinator is also permissible. Thus, for example, in various satisfactory forms of the apparatus, reaction chambers and condensers have been of glass, porcelain, and stainless steel tubings.

It has been found that various solid, inorganic catalysts, which may be termed dehydrochlorination catalysts," were found to be effective. Suchapplicable catalysts include the elemental metals iron, nickel, cobalt, uranium, vanadium, thorium, chr'omiumAzitanium, cerium, tungsten,

and silver, the inorganic compounds of these metals, such as ferric oxide, nickel oxides, cobalt oxides, cobalt chlorides, cobalt phosphates, uranium oxides (U0: and U03), vanadium oxides, thorium oxides, chromiumoxides, titanium oxides, cerium oxides, tungsten oxides, silver vanadate, ferric chloride, nickel chlorides, chromium chlorides, ferric phosphate, nickel phosphate, and so forth, and mixtures thereof. Thus, for example, carbon-steel wool or stainless-steel (a chromium-nickel steel alloy) wool can be used as the catalyst.

It was observed that materials of especially catalyst-packed, and evacuated reaction cham- 16 high degree of unsaturation were obtained by aeeaseo the use of cobaltous-cobaltic oxide (C0304); cobaltous chloride; cobaltous phosphate; a mixture of 75 percent cobaltous-cobaltic oxide and 25 percent uranium trioxide; a mixture of 75 percent cobaltous phosphate and 25 percent uranium phosphate; and a mixture of cobalt pyrophosphate, cobaltous oxide and cobaltous-cobaltic oxide. It has been found that especially good results are obtained when both a weak and a strong catalyst are used in conjunction. The two types of catalysts are arranged in separate zones, so arranged that the incoming vapors first contact the weak catalyst and then the strong catalyst. In this way, polymer formation is diminished and the channels through the catalyst are not plugged with resinous by-products. It has been found that, for the weak portion of the catalyst, it is preferred to use one of the metals or alloys referred to above in a form having extended surface, i. e., in the form of screen, mesh, gratings, turnings, wool, and so forth. In particular, we prefer to employ in this connection stainlesssteel (a chromium-nickel steel alloy) screen in the form of small U-shaped pieces. For the strong catalyst, any of the aforementioned cobalt compounds may be used.

Preferably, the catalysts are supported on a suitable carrier such as pumice, silica gel, active carbon, silicon carbide, coke, and so forth.

The following examples disclose the method of operation, and it is to be understood that these examples are given by way of illustration, and not limitation.

EXAMPLE I Use or STAINLESS-STEEL Woor. AS CATALYST Purified palmitic acid was chlorinated at 70 C. until approximately two equivalents of chlotime had been substituted per equivalent of acid. The product containing mono-, di-, and polychlorinated palmitic acids, as well as some unchanged palmitic acid, had a chlorine content of 22.6 percent (theoretical chlorine content of dichloropalmitic acid is 21.8 percent).

A U'-shaped tube was immersed in a heated oil bath. The chlorinated acid was fed into one leg of the tube at the rate of 3 grams per hour. The other leg of the tube was packed with 5.5 cm. of 18-8 stainless-steel wool (an alloy containing 18 percent chromium and 8 percent nickel), and this leg was connected through a condenser with a vacuum pump. The temperature of the oil bath was maintained at about 220 C., while the pressure in the condenser was held at slightly less than 1 mm. The chlorinated acid fed into the first leg of the tube was vaporized because of the high temperature and low pressure and the vapors passed upwardly through the catalyst column where the dehydrochlorination took place. The vapors leaving the catalyst zone were cooled and the unsaturated acids condensed. Wijs iodine value of the condensed product was taken as the index of its unsaturation. The product in this instance had an iodine value of 81.1.

EXAMPLE II COMPARISON OF DIFFERENT CATALYSTS The process of Example I was repeated, employing different catalysts for the purpose of comparing their effects, but using the same starting material and the same apparatus and conditir ng as set forth in Example I. In each run, the reaction leg of the U-tube was packed with 5.5 cm. of the particular catalyst under test.

Granules of pumice (2-3 mm.) were used to support the trial catalysts in most instances. Runs were also made with no. catalyst and with glass wool and pumice for purposes of comparison.

The results obtained are shownin the following table:

Team: I

Tests of various substances as dehydrochlorination catalysts for dichlorinated palmitic acidat 220 C. and 1 mm. pressure I Wijs iodine Trial catalyst Support value of product None 1 '3. 1 Glass wool l 6. 6 Granular pumice 23. 6 Carbon-steel wool. 44. 5 Fe,0,.. 56.8 NiO 6|. 2 C0;() 106. 0 00C], 128. 0 0030 04), 135. 7

An apparatus was set up which was adapted to larger-scale operations. The reaction chamber was a vertical glass tube in which the lower 10.5 cm. portion was packed with stainless-steel screen (a chromium-nickel ferrous alloy) and the upper 26.5 cm. portion packed with cobaltous chloride-pumice catalyst. This reaction tube was surrounded by an electrical heating apparatus. The reaction tube was connected at its lower end to a preheating tube which served to va-, porize the chlorinated acid entering the system. The chlorinated acid vapors then passed up the reaction tube, contacting first the stainless steel and then the cobaltous chloride-pumice catalyst. The vapors issuing from the upper part of the reaction tube were passed into a condenser.

The dichlorinated palmitic acid (prepared as described in Example I) was fed into the system at the rate of 0.5 gram per minute, the catalyst chamber being maintained at about 270 C. and the pressure being maintained at about 3.2 mm. of mercury. The estimated linear velocity of the feed vapor entering the catalyst-packed zone was about 200 cm. per second, while the velocity of the vapors just before leaving the catalyst was about 2,700 cm. per second. It was found that filling the lower 10.5 cm. of the catalyst tube with U-shaped bits of punched stainless-steel screen had the effect of decreasing polymer formation. Stainless steel apparently operates as a weaker catalyst, and when the vapors first contact the weaker catalyst before striking the stronger catalyst, the formation of polymers is drastically reduced. The dimensions of the granules of cobaltous chloride-pumice catalyst used to fill the upper 26.5 cm. of the tube were about 9-11 mm.

A total of 142.6 grams of chlorinated acid was fed into the system and 108 grams of unsaturated product obtained, 1, e., 96.7 percent of theory. The product had a chlorine content of 3.30 percent and an iodine value (Wiis) of 138.8.

The

A series of experiments was carried out, using the apparatus described in Example 111. In each case di-chlorinated palmitic acid (prepared as described in Example I) was fed into the system at the rate of 0.5 gram per minute. In all the experiments except No. 1, the catalyst tube was packed with stainless-steel screen and cobaitous chloride-pumice catalyst as described in Example 111. In experiment No. 1, the catalyst tube was packed with 26 cm. of the cobaitous chloridepumice catalyst alone. The catalyst used in experiment No. was previously employed in experiment No. 4. In experiment No. 7, the pumice used for preparing the catalyst wa digested in hydrochloric acid, washed free oi acid, and dried before impregnation with cobaitous chloride.

The following table sets forth the conditions of operation and the results obtained:

I his value oi prodnot (Wljs) 1%.0l 124. 5 132. 9

In this or riment cobaitous-chloride catalyst was used alone. The lower yie d indicates greater polymer formation when the single catalyst is used in comparison with the other experiments when the dual catalyst was employed.

The unsaturated products were clear, pale orange-colored liquids at slightly above room temperature: 'At room temperature they partially crystallized. They showedno tendency to discolor with age when protected from oxygen and mineral acids. I

EXAMPLE V Dsnrnsocmornn'rron or Canonnwrxp Ourc Acm A 0.9 N solution of chlorine in methylene chloride, cooled to about -20 C., was slowly poured into a 10 percent solution of pure oleic acid in the same solvent at the same temperature. The temperature oi the mixture was not allowed to rise above 8 C. during the addition. The quantity of chlorine added was limited to 95 percent or the amount required for saturation of the oleic acid. After mixing, the solution was purged of chlorine by bubbling a stream of. nitrogen through it. The chlorinated acid was recovered by distillation under reduced pressure. The chlorinated product contained 18 percent chlorine and had an iodine value 01! 9.6. The product contained 8'! mol percent 9,10-dichlorostearic acid and 13 mol percent of 01610 acid.

The chlorinated acid was dehydrochlorinated in the apparatus described in Example HI, utilizing the stainless-steel screen and cobaitous chloride-pumice dual catalyst as describedtherein. The chlorinated acid was fed into the system at the rate of 0.5 gram per minute. The temperature and pressure were maintained at about 270 C. and about 1.3 mm., respectively. The product contained 3.1 percent of chlorine and was obtained in a yield of 75.5'percent. The iodine value 01' the product (Wils) was 96.3.

EXAMPLE VI rate of 0.5 gram per minute. The temperature and pressure were maintained at about 280 C. and about 1.3 mm., respectively. The product contained 8.4 percent chlorine and was obtained in'a yield of 70.4 percent. The iodine value (Wiis) oi the product was 157.7.

Exempt: VII

A series of experiments were carried out, employing the apparatus described in Example I. The chlorinated materials were fed into the system at the rate of 3 grams per hour. The reaction leg of the tube was filled with 5.5 cm. of the cobaitous chloride-pumice catalyst. The results are disclosed in the following table.

Tans: 111

Experiment N 0.

Starting material 1 2 3 4 5 Chlorin- Ohlorin- Ghlorin- Ohlorin- Chlorinated ated ated ated ated stearic palmitic methyl palruitic linoleic acid 1 acid 1 paimitate acid acid l 2) 1 22.1 21.6 18.1 30.7 1 0 1.0 1.0 1.0 1.1 240 2%) 220 220 $5 0.7 1.5 11.5 1.4 2.4 Yield, percent I 80.0 88.0 93.0 85.0 55.0 Iodine value of product (Wile) 131. 0 130.2 81.3 134.6 139.4

1 The chlorinated stearic acid (It The chlorinated acid contained H.175

E. No. 1) was prepared b direct chlorination oi purified stearic acid.

(theoretical for di crostearic acid, 20.07%).

i The chlorinated palmitlc acid (Exp. No. 2) was prepared as in Example I; it contained 22.1% chlorine (theoretical for dichloropalrnitic acid, 21

1 The chlorinated methyl palm-lute C The chl paimitate at 40 to mitatc 20.0%).

orinated ester contained 21.6% chlorine (theoretical for met xp. No. 3) was prepared by direct chlorination oi lruethayil y orop 4 he chlorinated palmitic acid (Exp. No. 4) was prepared by saponiiicatio gt the chlorinated methyl palrnitate described above (footnote 3).

i The chlorinated linoleic acid (Ex No. 5) was obtained by chlormatiug linoleic acid obtained from sunflower-seed oil fatty acids.

The same tion technique was used as in connection with oleic acid (Example V). The chlorinated acid had an iodine-value of 4.6 and a chlorine content of 30.7 (theoretical tor tctrachlorostearic acid, 33.50%

The gilelds in these experiments are estimated to be from 5 to 15% lower than actual because of re d prod at c d p" The process of the invention can be applied to a wide range of chlorinated acids and esters to obtain unsaturated products. Thus, the process can be applied to mono-, di-, or polychlorinated fatty acids having from 8 to 20 carbon atoms or their esters with short chain alcohols. Thus, use can be made of the mono-, di-, or polychlorinated derivativesof caprylic, pelargonic, capric, undecylic, lauric, tridecylic, myristic, pentadecylic, palmitic, stearic, margaric, nondecylic. arachidic, oleic, undecylenic, elaidic, ricinoleic, palmitaleic, erucic, brassidic, and linoleic acids.

In addition to the chlorinated fatty acids, the process can be applied to the short chain alkyl esters of the chlorinated fatty acids. It has been found that the methyl and ethyl esters of the chlorinated fatty acids give results most nearly comparable with those obtained with the chlorinated fatty acids themselves. Mixtures of chlorinated fatty acids or chlorinated fatty acid esters also can be used.

Some particular materials which are particularly adapted to be used are listed below, although it is to be emphasized that these examples are given by way of illustration and not limitation, i. e., monochlorinated palmitic acid, dichlorinated-palmitic acid, trichlorinated palmitic acid, tetrachlorinated palmitic acid, monochlorinated methyl palmitate, dichlorinated methyl palmitate, trichlorinated methyl palmitate, tetrachlorinated methyl palmitate,. monochlorinated ethyl palmitate, dichlorinated ethyl palmitate, trichlorinated ethyl palmitate, tetrachlorinated ethyl palmitate, monochlorinated stearic acid, dichlorinated stearic acid, trichlorinated stearic acid, tetrachlorinated stearic acid, monochlorinated methyl stearate, dichlorinated methyl stearate, trichlorinated methyl stearate, tetrachlorinated methyl stearate, monochlorinated ethyl stearate, dichlorinated ethyl stearate, trichlorinated ethyl stearate, tetrachlorinated ethyl stearate, monochlorinated arachidic acid, dichlorinated arachidic acid, trichlorinated arachidic acid, tetrachlorinated arachidic acid, monochlorinated methyl arachidate, dichlorinated methyl arachidate, trichlorinated methyl arachidate, tetrachlorinated methyl arachidate, monochlorinated ethyl arachidate, dichlorinated ethyl ara chidate, trichlorinated ethyl arachidate, tetrachlorinated ethyl arachidate, monochlorinated oleic acid, dichlorinated oleic acid, trichlorinated oleic acid, tetrachlorinated oleic acid, monochlorinated methyl oleate, dichlorinated methyl oleate, trichlorinated methyl oleate, tetrachlorinated methyl oleate, monochlorinated ethyl oleate, dichlorinated ethyl oleate, trichlorinated ethyl oleate, tetrachlorinated ethyl oleate, Likewise, the corresponding mono-, di-, tri-, and tetrachlorinated derivatives of other fatty acids such as caprylic, pelargonic, capric, undecylic, lauric, tridecylic, myristic, pentadecylic, margaric, nondecylic, undecylenic, elaidic, ricinoleic, palmitoleic, erucic, brassidic, linoleic, and so forth, can be used as well as the corresponding methyl and ethyl esters. Mixtures of these chlorinated fatty acids, mixtures of these chlorinated fatty acid esters, or mixtures of both can be used.

These compounds listed above are not necessarily pure, individual compounds, but they may have an average composition represented bytheir names. Thus, monochlorinated stearic acid refers to either the individual compound or the mixture of isomers prepared by reacting chlorine with stearicacid until the product contains an average of one atom of chlorine per stearic acid l0 molecule. This method of chlorinating acids is preferred because it is simple, economical, and gives good results. It is possible, of course, to use particular individual chlorinated comopunds. Thus, by reacting oleic acid with chlorine under mild conditions to obtain only addition, 9,10-dichlorostearic acid, an individual compound is prepared. Other individual compounds of this type which may be used are methyl 9,10-dichlorostearate, ethyl 9,10-dichlorostearate, 9, 10, 12,13- tetrachlorostearic acid (by chlorination of linoleic acid), methyl 9,10,12,13-tetrachlorostearate, 2- chlgropalmitic acid, 2,3-dichloropalmitic acid, 2- chlorostearic acid, 2,3-dichlorostearic acid, and so forth.

Furthen it is not necessary to use purified or individual fatty acids. The mixtures of homoloous fatty acids obtainable in commerce by the hydrolysis of natural fats and oils are very useful. Thus, one may chlorinate the mixture of fatty acids obtained .by hydrolyzing coconut oil, palm-kemel oil, tallow, suet, cottonseed oil, peanut oil, lard, olive oil, whale oil, sardine oil, corn oil, soybean oil, and so forth. Thus, one may acids, dichlorinated suet fatty acids, trichlorinated suet fatty acids, tetrachlorinated suet fatty acids, monochlorinated cottonseed fatty acids, dichlorinated cottonseed fatty acids, trichlorinated cottonseed fatty acids, tetrachlorinated cottonseed fatty acids, monochlorinated peanut fatty acids, dichlorinated peanut fatty acids, trichlorinated peanut fatty acids, tetrachlorinated peanut fatty acids, monochlorinated lard fatty acids, di-' chlorinated lard fatty acids, trichlorinated lard fatty acids, tetrachlorinated lard fatty acids, monochlorinated soybean oil fatty acids, dichlorinated soybean oil fatty acids, trichlorinated soybean oil fatty acids, tetrachlorinated soybean oil fatty acids, monochlorinated olive oil fatty acids, dichlorinated olive oil fatty acids, trichlorinated olive oil fatty acids, tetrachlorinated olive oil fatty acids, monochlorinated whale oil fatty acids, dichlorinated whale oil fatty acids, trichlorinated whale oil fatty acids, tetrachlorinated whale oil fatty acids, monochlorinated sardine oil fatty acids, dichlorinated sardine oil fatty acids, trichlorinated sardine oil fatty acids, tetrachlorinnated sardine oil fatty acids, monochlorinated corn oil fatty acids, dichlorinated corn oil fatty acids, trichlorinated corn oil fatty acids, tetrachlorinated corn oil fatty acids. In this manner, highly unsaturated fatty acids can be prepared from cheap raw materials by a simple and economical process. By the technique of this invention, a double bond is introduced for each chlorine atom present. Thus, if the starting material contains one chlorine atom per molecule, the

. product will contain one double bond; if the unsaturated fatty acid which will soluble soap than stearic acid, one introduces an produce a more average of one chlorine atom into the stearic acid molecule. The product will contain an average 8 one double bond and will be eminently suitable for preparlngsoap. n the other hand, if itis.

desired to prepare a drying oil from oleic acid,

two or more chlorine atoms are introduced, and

then the product will be highly unsaturated and maybeusedtoprepareadryingioil byesteriiicaition' with glycerine.

good soap because sodium stearate has low solubility. By hydrolyzing the natural fat, the fatty acids high, in stearic acid can be converted by our process into unsaturated-derivatives. Such unsaturated fatty-acids, when saponified, form.

soaps much more soluble than stearates and having good surface active properties. Likewise, by

'chlorinating to a higher degree, compounds having two or moredouble bonds per molecule can be prepared. These compounds, by reason of their highly unsaturated nature, are eminently suitable for preparing drying oils, and so forth.

1 It has been found that when oleie acid, chlorinated by addition to form chiefly 9.,l0-dlchlorostearic acid, is subjected to dehydrochlorination according to the instant technique, products having two conjugated double bonds are formed. Thus, the products prepared from dichlorinated oleic acid are eminently suitable for preparing drying oils by esteriflcation with glycerol, pentaerythritol, and so forth.

The following examples illustrate some of the uses to which the unsaturated products of this invention may be applied.

EXAMPLE VIII Four-rm: Tss'rs A soap was prepared, in the usual manner, from the unsaturated product obtained from dichlorlnated palmitic acid (Example 2). This soalp was compared with standard soaps according to the technique specified in Bureau of Ships ad interim specifications, 51 S 46 (I. N. T.), December 1, 1943, and 51 D 7 (I. N. T.), November 1,

EXAMPLEIX WrrrnwcTlsrs- Tests were made of the relative concentrations of wetting agents in solution required to cause chains of cotton yarn to sink within a definite .j time under set conditions. The following results were obtained:

Soiled cloth washed with soa Tuna: V

Agent Agent Soapoftadmiealoldeacld... 1.00 A cumnmdal deter-amt consisting of amixtin-aoi aodiumalkylbculmasulphmatasiree iruminorgauiclltsn- L03 Soapdumatm-ated acids obtained from dichlorinated palmiticacldaccordingtothisinmiion. 0.81

EXAMPLE 1:

'Waarrmc TISTS Swatches of white woolen flannel were soiledand washed according to the specifications referred to in Example VIII. Relative emciencies of the detergents used were indicated by refle'ctance measurements made on the washed swatches.

Tam: VI

Average Unsoilod washed cloth Boiled cl h Boiled cloth washed withcoconut oil soap of unsaturated acids obtained from dichlorina palmitic acid according to this invention EXAMPLE Xi Use: as Dams On.

The unsaturated product obtained from dichlorinated oleic acid (Example V) was esterifled with pentaerythritol. The ester .was mixed with thinner and japan drier and coated on glass. Upon drying overnight a hard, transparent film was formed on the glass. Similar results were obtained when the unsaturated acid was esterifled with a commercial mixture of pentaerythritol and dipentae'rythritoL' Having thus described our invention, we claim:

1. A process for dehydrochlorinating a compound selected from the group consisting of high molecular weight chlorinated fatty acids and the alkyl esters thereof, comprising contacting said compound in the vapor phase with a solid dehydrochlorination catalyst selected from the group consisting of the elemental metals vanadium, chromium, iron, cobalt, and nickel, the inorganic compounds of these metals, and mixtures thereof, at a temperature of about from 220 C. to 300 C. and at a pressure below 5 mm. of mercury.

2.A process for dehydrochlorlnating a compound selected from the group consisting of high molecular weight chlorinated fatty acids and the alkyl esters thereof, comprising contacting said compound in the vapor phas with a solid, inorganic cobalt compound at a temperature of about from 220 C. to 300 C. and at a pressure below 5 mm. of mercury.

3. A process: for dehydrochlorinating a compound selected from the group consisting of high molecular weight chlorinated fatty acids and the alkyl esters thereof, comprising contacting said compound in the vapor phase first with a solid dehydrochlorination catalyst selected from the group consisting of the elemental metals vanadium, chromium, iron, cobalt, and nickel, the inorganic compounds of these metals, and mixtures thereof, in a form having extended surface, and second, with a solid, inorganic cobalt compound supported on a suitable carrier, said 13 contacting being carried out at a temperature of about from 220 C. to 300 C. and at a pressure below mm. of mercury.

4. A process for dehydrochlorinating a compound selected i'rom the group consisting of high molecular weight chlorinated fatty acids and the alkyl esters thereof, comprising contacting said compound in the vapor phase, first with a chromium-nickel steel alloy in a form having extended surface, and second with a solid, inorganic cobalt compound supported on a suitable carrier, said contacting being carried out at a temperature of about from 220 C. to 300 C. and at a pressure below 5 mm. of mercury.

'5. A process for dehydrochlorinating a high molecular weight chlorinated fatty acid, comprising contacting said acid in the vapor phase with a solid dehydrochlorination catalyst selected from the group consisting of the elemental metals vanadium, chromium, iron, cobalt, and nickel, the inorganic compounds of these metals, and mixtures thereof, at a temperature of about from surface. and second with cobalt chloride supported on a suitable carrier, said contacting being carried out at a temperature of about from 220' C. to 330 C. and at a pressure below 2 mm. of

mercury.

12. A process for dehydrochlorinating a chlorinated palmitic acid containing an average of 2 atoms of chlorine per molecule, which comprises contacting said acid in the vapor phase, first with a chromium-nickel steel alloy in a. form having extended surface, and second with cobalt chloride supported on pumice granules, said contacting being carried out at a temperature of about from 220 C. to 300 C. and at a pressure below 2 mm. of mercury.

13. A process for dehydrochlorinating chlorinated stearic acid which comprises contacting said acid in the vapor phase with a solid, inorganic cobaltcompound at a temperature of about from 220 C. to 300 C. and at a pressure below 2 mm.

of mercury.

220 C. to 300 C. and at a pressure below 5 mm.

of mercury.

8. A process for dehydrochlorinating a high molecular weight chlorinated fatty acid, comprising contacting said acid in the vapor phase with a solid; inorganic cobalt compound at a temperature of about 220 C. to 300 C. and at a pressure below 5 mm. of mercury.

'7. A process for dehydrochlorinating a high molecular weight chlorinated fatty acid, comprising contacting said acid in the vapor phase, first with a solid dehydrochlorination catalyst selected from the group consisting of the elemental metals vanadium, chromium, iron, cobalt, and nickel, the inorganic compounds of these metals, and mixtures thereof, jna form having extended surface, and second with a solid, inorganic cobalt compound supported on a suitable carrier, said contacting being carried out at a temperature of about from 220' C. to 300 C. and at a pressure below 5 mm. of mercury.-

8. A process for dehydrochlorinating. a high molecular weight chlorinated fatty acid, comprising contacting said acid in the vapor phase, first with a chromium-nickel steel alloy in a form having extended surface, and second with a solid, inorganic cobalt compound supported on a suitable carrier, said contacting being carried out at a temperature of about from 220 C. to 300 C. and at a pressure below 5 mm. of mercury.

9. A process for dehydrochlorinating chlorinated palmitic acid which comprises contacting said acid in the vapor phase with a solid, inorganic cobalt compound at a temperature of about from 220 C. to 300 C. and at a pressure below 2 mm. of mercury.

10. A process for dehydrochlorinating chlorinated palmitic acid which comprises contacting said acid in the vapor phase. first with a chroml-um-nickel steel alloy in a form having extended surface, and second with a solid. inorganic cobalt compound supported on a suitable carrier, said contacting being carried out at a temperature of about from 220 C. to 300 C. andat a pressure below 2 mm. of mercury.

11. A process for dehydrochlorinating chlorinated palmitic acid which comprises contacting 14. A process for dehydrochlorinating chlorinated stearic acid which comprises contacting said acid in the vapor phase, first with a chromiumnickel steel alloy in a form having extended surface, and second with a solid, inorganic cobalt compound supported on a suitable carrier, said contacting being carried out at a temperature of about from 220 C. to 300 C. and at a pressure below 2 mm. of mercury.

15. A process for dehydrochlorinating chlorinated stearic acid which comprises contacting said acid in the vapor phase, first with a chromiumnickel steel alloy in a form having extended surface, and second with cobalt chloride supported on a suitable carrier, said contacting being carried out at a temperature of about from 220 C. to 300 C. and at a pressure below 2 mm. of mercury.

16. A process for dehydrochlorinating a chlorinated stearic acid containing an average of 2 atoms of chlorine per molecule which comprises contacting said acid in the vapor phase, first with a chromium-nickel steel alloy in a. form having extended surface, and second with cobalt chloride supported on pumice granules, 1 said contacting being carried out at a temperature of about from 220 C. to 300 C. and at a pressure below 2 mm. of mercury.

17. A process for dehydrochlorinating 9,10-

REFERENCES crrEn The following references are of record in the file of this patent:

UNITED STATES PATENTS 2,288,580 Baehr et al. June 80, 1842 

